Mobile water treatment and resin transfer hub

ABSTRACT

A system and method for providing mobile or temporary water treatment involving ion exchange resins includes a service centre, one or more treatment vehicles, a resin transfer hub and one or more resin transport vehicles. The service centre can be used to regenerate one or more types of ion exchange resins. The treatment vehicle carries water treatment equipment including a tank holding ion exchange resin. The resin transfer hub facilitates moving resin between a treatment vehicle and a resin transport vehicle. The resin transport vehicle is adapted for carrying resin by one or more of land, sea and air between the resin forwarding centre and the service centre. In operation, a treatment vehicle brings resin requiring regeneration to the resin transfer hub, where it is emptied and then re-filled with regenerated resin. Resin requiring regeneration is transferred to a resin transport vehicle for transport to the service centre. The resin transport vehicle is re-filled there with regenerated resin, which is taken back to the resin transfer hub for transferred to a treatment vehicle.

FIELD

This specification relates to water treatment using ion exchange resinsand to a system and method for providing mobile or temporary watertreatment involving ion exchange resins.

BACKGROUND

In a mobile water treatment system, water treatment equipment isprovided in a portable vehicle, such as a truck, trailer, skid ortransport container, and delivered to a location where water treatmentis required. Such mobile water treatment systems are used when it wouldbe less economical to build a permanent treatment plant. For example,temporary water treatment may be required when a power plant iscommissioned; when permanent water treatment plants are being repaired;for forestry or mining camps; or, to provide feed water for boilers thatoperate seasonally. In general, treated water may be required at aparticular site for a period of time that may be up to several years butis still less that the lifetime of a permanent water treatment plant.Alternatively, treated water may be required permanently but for onlypart of each year, for example between about 1,000 to 2,000 hours peryear. In both of these cases, it can be less expensive for the siteoperator to rent a mobile water treatment system than to build apermanent facility.

The vehicle in a mobile water treatment system may be fitted with, amongother things, various sorts of tanks, media, pumps, pipes, controls andinstrumentation. In the MobileFlow™ system by GE Water & ProcessTechnologies, for example, a transport truck trailer is fitted with sixtanks that are made of steel, lined with rubber, and capable of beingpressurized to 100 psi. The tanks are connected together with a standardpiping system that allows the tanks to be connected together in seriesor parallel. Each tank can be filled with one of a selection ofavailable media types such as granular filter media, deoxygenationmedia, or ion exchange resin beads. For example, to providedemineralization treatment some tanks are filled with cation exchangeresin, other tanks are filled with strong base anion exchange resin, andanother tank is filled with a mixed bed. Each trailer also includes aninstrumentation package, a controls package and a heating system. Thetrailer is set up and tested at a service centre, and then trucked tothe treatment site to be put in operation.

In cases where resin beds are used, the resin beads must be regeneratedfrom time to time. In the MobileFlow™ system, the vehicle is returned tothe service centre where the resin beads are transferred intoregeneration vessels and stored there until the beads can beregenerated. Previously regenerated resin is transferred back on to thevehicle, which can then be sent back to the same or another watertreatment site. In this way, water for regeneration is not required atthe treatment site, which may be in a water scarce location, andregeneration waste water does not need to be discharged at the watertreatment site, which may not have a waste water discharge permit.Further, comprehensive regeneration processes, including for examplebackwashing and air scrubbing, treatment with regenerants, rinsing withdeionized water and quality testing, can be provided at the servicecentre.

INTRODUCTION TO THE INVENTION

Mobile water treatment systems provide a valuable service, saving manyusers of treated water the cost of building their own treatment plant.However, building a service centre is a significant expense, on theorder of several million dollars. Accordingly, it is desirable to obtainthe maximum possible use from a service centre by having it serve a verylarge service area. This in turn may require having treatment systemtrailers moving at times over very long distances. Towards the edges ofa service area, the trailers may need to cross through multiple statesor provinces in a North American market, or cross through multiplecountries in a European or Asian market, to move between a servicecentre and a treatment site. For treatment systems using ion exchangeresins that are returned from time to time to the service centre forregeneration, the cost of moving the trailers can add significantly tothe cost of providing treated water at the site.

A system and method for providing mobile or temporary water treatmentinvolving ion exchange resins are described in this specification, alongwith a resin transfer hub for use in the system. The system includes aservice centre, one or more treatment vehicles, a resin transfer hub,and one or more resin transport vehicles. The service centre is used,possibly among other things, to regenerate one or more types of ionexchange resins. A treatment vehicle may be a trailer or any other typeof vehicle, including a container adapted to be carried by anothervehicle, that is transportable by land, sea or air and carries watertreatment equipment including a tank for holding ion exchange resin. Theresin transfer hub is a facility located permanently or temporarilyapart from the service centre for moving resin between a treatmentvehicle and a resin transport vehicle. Optionally, additional items suchresin storage vessel or a make up water supply system may be providedwith or in the resin transfer hub. The resin transport vehicle is avehicle, which may include a container capable of being carried byanother vehicle, adapted for transporting resin by land, sea or airbetween the resin transfer hub and the service centre.

In operation, one or more treatment vehicles may be transported directlyto and from the service centre when they contain resin requiringregeneration. However, one or more treatment vehicles may alternativelybring resin requiring regeneration to the resin transfer hub, to beemptied and then re-filled there with regenerated resin. The resintransfer hub is used to transfer resin requiring regeneration to a resintransport vehicle, directly or through an intermediate storage step. Theresin transport vehicle transports resin requiring regeneration to theservice centre and is re-filled there with regenerated resin. Theregenerated resin is taken back to the resin forwarding centre fromwhere it can be transferred into one or more treatment vehicles.

One possible advantage of the system is a reduction in thetransportation or system capital costs required to supply treatmentsites far from the service centre with regenerated resin. This in turnmay allow a service centre to serve a larger service area, reducing theoverhead cost of the service centre per treatment site in the servicearea. If a treatment site must be shut down while its resin is beingregenerated, then down time at the treatment site may also be reduced.Savings in cost may result from one or more of the differences betweenthe treatment vehicle and the resin transport vehicle. The resintransport vehicle does not require multiple pressure resistant tanks orextensive piping, instrumentation, controls or heat. The resin transportvehicle may therefore be able to store more resin within the sameexternal dimensions, or within the same weight limitation, compared tothe treatment vehicle. The resin transport vehicle can also be lessexpensive than a treatment vehicle and thereby decrease the total costof the vehicle inventory of the system, or all for more vehicles withinthe same total cost. Using the resin transport vehicle for long haulshipping may also reduce damage during transport to instruments andcontrols in the treatment vehicle. The resin transport vehicle may alsobe more easily or economically provided in the form of an ISO or otherintermodal container, which may allow for shipment by two or more ofroad, rail, sea or air. Optionally, the resin transport vehicle may beable to also function as storage vessel while at the resin transfer hub.Further optionally, the resin transfer hub may be portable such that theresin transfer hub can be moved if the location of distant treatmentsites changes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic overview of a system for providing mobile ortemporary water treatment involving ion exchange resins.

FIG. 2 is a side view of a treatment vehicle.

FIG. 3 is a side view of a resin transport vehicle.

FIG. 4 is a schematic illustration of a resin transfer hub and anoptional storage vessel and make up water polishing system.

DETAILED DESCRIPTION

An example of a system and method for providing mobile or temporarywater treatment involving ion exchange resin, and a resin transfer hub,will be described below.

Referring to FIG. 1, a service area 10, represented by a large area ofland 12, has a service centre 14 located in one part of it. The servicecentre includes equipment for regenerating spent ion exchange resins. Atthe service centre 14, resin beads needing regeneration are transferredfrom a vehicle carrying them to storage vessels where the beads can beregenerated. The regeneration process may include, for example, an airscrub, backwash, chemical regenerant application and deionized waterrinse. The regenerated resin may also be tested or analyzed to determinethe degree or quality of the regeneration. For mixed resin beds, thereare also additional steps of separating the mixed bed before the resinis regenerated and, optionally, re-mixing the resins. The regeneratedresin beads can then be transferred back to a vehicle. While someresins, particularly cation resins used in water softening, may beregenerated with relatively harmless chemicals such as salt, otherresins are regenerated with strong acids, such as hydrochloric acid, ora caustic such as sodium hydroxide. Accordingly, the service centre 14is located in an area where water treatment facilities or dischargepermits are available. Further, due to the need to provide regenerationand rinse water, the service centre 14 is also located in an area inwhich water for these tasks is available.

Resin may be loaded from the service centre 14 into one or moretreatment vehicles 16 for transport to a treatment site 18. Thetreatment site 18 may be, for example, a power station, a factory, amining or forestry camp, or a factory with a boiler. The treatmentvehicle 16 may be, for example, a transport truck trailer 20 as shown inFIG. 2. This treatment vehicle 16 is fitted with tanks 21, a pipingnetwork 23, and a controls, instrumentation and heating package 26.Various connections are provided to the tanks including a liquid inlet,a liquid outlet and a compressed air fitting. When the treatment vehicle16 is used to treat water using ion exchange resins, for example toprovide demineralization, softening or condensate polishing, one or moreof the tanks 21 are filled with resin from the service centre 14 beforethe treatment vehicle 16 is deployed at a treatment site 18. As shown bytreatment vehicle 16 a, the treatment vehicle 16 also travels back tothe service centre 14 from time to time so that the resins that itcontains can be regenerated. Optionally, a substitute treatment vehicle16 may be sent to a treatment site 18 requiring regeneration before itsoperating treatment vehicle 16 is removed. In that case, the firsttreatment vehicle 16 becomes the substitute treatment vehicle 16 once itis removed from the treatment site 18, and might not return to the sametreatment site 18.

One or more of the treatment sites 18 may be located far from theservice centre 14. Further, the most efficient transport method to theremote treatment sites 18 may be by means other than truck, for exampleby rail or ship. In FIG. 1, for example, a body of water adds to thealready lengthy distance required to reach the remote treatment sites 18by truck. For shipping resin to or from distant treatment sites 18, aresin transport vehicle 28 is used to carry resin between the servicecentre 14 and a resin forwarding centre 20. When a treatment vehicle 16,such as the treatment vehicle 16 b shown in FIG. 1, has resin that needsto be recharged, the treatment vehicle 16 travels to the resinforwarding centre 20 to drop off its spent resin and to be re-filledwith regenerated resin.

Referring to FIG. 3, an example of a resin transport vehicle 28 has aframe 30 that is fitted with a large tank 32. The frame 30 may be of astandard size and may be fitted with standardized mounting points 36such that is can function as an ISO inter-modal shipping container. Thetank 32 has an outlet 34 for discharging resin from the tank 32 and aninlet 33 for filling the tank 32 with water or a slurry of resin beadsin water. The outlet 34 is located near the bottom of the tank 32 andprovided with one or more valves. The outlet 34 may also be fitted witha chamber 37 adapted to accept a removable screen 39 having a mesh sizesufficiently small to retain resin beads in the tank 32 while allowingwater to drain out. The inlet 33 is located at the top of the tank 32,optionally in the opposite end of the tank 32 from the outlet 34. Theinlet 33 may also have a nozzle 35 directed generally toward the outlet34. The nozzle 35 assists in using water sprayed through the inlet 33 toforce resin from the tank 32. The tank 32 also has a compressed airfitting 31. The resin transport vehicle 28 may have a capacity of 20cubic meters or more, which may be greater than the capacity of all ofthe tanks in the water treatment vehicle 16.

Referring to FIG. 4, the resin transfer hub 22 may be located with oneor more optional storage vessels 24, for example a silo. The storagevessel 24 may have a liquid inlet, a liquid outlet and a compressed airfitting. An optional water polishing unit 20 may also be provided. Theresin transfer hub 22 may be transportable and can be moved if thelocation of treatment sites 18 changes over time. For example, the resinhub 22 may be built inside of a 40 foot long high cube shippingcontainer that can be moved by truck, rail or boat. The resin hub 22 isequipped for moving resin beads between any two tanks, for examplebetween a storage vessel 24 and a treatment vehicle 16, between astorage vessel 24 and a resin transport vehicle 28, or between a resintransport vehicle 28 and a treatment vehicle 16.

To move resin beads, the resin transfer hub 22 has a water circulationsystem 40 and a compressed air supply system 38. The water circulationsystem 40 has a tank 42, which may have a volume of 10 cubic meters ormore. The tank 42 also has a vent 44 and an overflow pipe 46. One ormore outlets 48 of the tank are connected to one or more liquid pumps 50which are in turn connected to one or more fittings 52 for connectingthe outlet side of a pump 50 to a pipe or a fitting on a treatmentvehicle 16, storage vessel 24 or resin transport vehicle 28. One or moreinlets 54 allow water returning from a treatment vehicle 16, storagevessel 24 or resin transport vehicle 28 to return to the tank 42.

A make up water inlet 56 may be used to provide make up water to thetank 42. The make up water is preferably deionized water so that waterused in transferring regenerated resin will not use up any significantpart of the capacity of the resin. Deionozed water may be obtained bytreating municipal supply water from time to time through a treatmentvehicle 16 on its way to or from a treatment site 18, or by a small theoptional water polishing unit 20. The water polishing unit has one ormore resin tanks 60 filled with cation, anion and mixed resin beds totreat raw water. A by-pass line 62 is provided to allow alreadydeionized make up water, when available, to be filled directly into thetank 42.

The compressed air supply system 42 uses a compressor, for example aturbine 64, to supply compressed air to a reservoir 66. The reservoir 66is in turn connected to one or more air outlets 68 for providing thecompressed air to a treatment vehicle 16, storage vessel 24 or resintransport vehicle 28. The resin transfer hub 22 may also have variousancillary components such as valves, sensors, gauges, or controllers asmay be desirable for recirculating water through, and providing air to,a treatment vehicle 16, storage vessel 24 or resin transport vehicle 28.

In transferring resin beads, a first treatment vehicle 16, storagevessel 24 or resin transport vehicle 28 provides a tank being emptiedand a second treatment vehicle 16, storage vessel 24 or resin transportvehicle 28 provides a tank being filled. The tank being emptied isfilled with water from the tank 42 of the resin hub 22 to above thelevel of the resin beads. The tank being emptied is then pressurizedwith compressed air, for example to 20 to 30 psi. Opening an outletvalve in the tank being emptied allows a slurry of water and resin beadto flow through a transfer pipe connected between the outlet of the tankbeing emptied and an inlet of the tank being filled. Additional watermay be pumped from the tank 42 into the tank being emptied, or directlyinto the transfer pipe, to aid in moving the resin slurry. The waterused in the transfer drains from the tank being filled back to the tank42 of the resin hub 22 through a return pipe for reuse. If not providedin with the outlet of the tank being filled, a strainer in the returnpipe keeps resin beads from flow back to the tank 42. Water drainingback to the tank 42 may be recirculated back to the tank being emptiedto help move the resin beads, particularly when the tank is nearlyempty.

Almost all, for example 95% or more, of the resin in the tank beingemptied may be transferred to the tank being filled as described above.Some resin beads may remain at the bottom of the tank being emptied, butcan be removed later, for example by flushing these remains into filterbags. Some resin beads may also remain in the pipe, but can be removedlater, for example by flushing the pipe. If the tank being emptied is alonger than it is high, such as the resin transport vessel 28, one endof the tank may be raised so that the tank bottom slopes towards theresin outlet.

Other means of transferring resin, or enhancing the movement of resin,may also be used. For example, compressed air can be provided or arecirculating flow of water may be provided from the bottom of a bed ofresin to fluidize the bed allowing it to flow more easily, possibly bygravity. An impeller may also be used to fluidize the bed. A positivedisplacement diaphragm pump may be used to move the slurry through atransfer pipe between the tank being emptied and the tank being filled.As a further alternative, the tank being emptied may be filled withwater and a drain pipe may be connected upstream of an ejector to forman eductor system. The ejector is fed with a flow of pressurized watercreating a local vacuum to draw resin into the ejector from where thepressurized water carries the resin beads through a transfer hose. Byany of these methods, a flow of resin beads in a slurry can be made toflow through a pipe that discharges into the tank being filled.

If a mixed bed is required in the treatment vehicle 16, the mixed bedmay be prepared in a mixing tank, which may be a tank of the treatmentvehicle 16 that will use the mixed bed. Alternatively, any other tank inany vehicle or vessel 16, 24 or 28 may be used as the mixing tank, andthe mixed bed may be transferred to the treatment vehicle 16 after it ismixed. To prepare the mixed bed, appropriate amounts or cation and anionresin are separately loaded into the mixing tank. Water is added toabove the level of the resin beads. A vent or inlet at the top of themixing tank is kept open while compressed air flows into the tank fromnear the bottom of the mixing tank. While the compressed air continuesto flow, the water level in the mixing tank is lowered in steps or in aslow continuous drain. The compressed air flow is stopped when the waterlevel is at or near the bottom of the mixing tank, and the mixing tankis left to drain.

After a transfer of resin beads, the water used to fluidize the resinbeads is allowed to drain back in to the tank 42 for re-use. Optionally,compressed air my be supplied to the filled or emptied tank, or both, toassist with the draining. In the filled tank in particular, thecompressed air is useful for draining water from the resin bed. A screenis fitted at the outlet of a filled tank so that resin beads will not becarried back to the tank 42. Some water is lost due to incompletedraining of the filled tanks. The water in the tank 42 may also becometoo turbid to re-use, requiring that it be wasted, treated or diluted.The resin transfer hub 22 thus may use some water, but in vastly reducedamounts relative to the service centre 14 and without using ordischarging significant amounts of chemicals. The resin transfer hub 22may therefore be located in an area where water is scarce and wastewater treatment or discharge permitting is limited or not available.Optionally, the resin transfer hub 22 may be fitted with two tanks 42,one used for transferring regenerated resin and one used fortransferring spent resin. In this way, water used for transferringregenerated resin would remain clean longer, while water used totransfer spent resin may be allowed to become more turbid than would beacceptable for moving regenerated resin. Less make up water would berequired to maintain a supply of water at an acceptable quality fortransferring spent and regenerated resin.

Separate resin storage vessels 24, if any, may be provided for cationresins and anion resins and mixed resins and resin transport vessels 28may be filled with only cation resins or only anion resins whentransporting regenerated resin to the resin hub 22. In this way, theresin hub 22 does not need to be provided with resin separationequipment. However, resin separation equipment may optionally beprovided in the resin hub 22. For the return of spent resin from theresin hub 22 to the service centre 24, resins of different types may betransferred into a single resin transport vessel 28 provided the servicecentre has resin separation equipment.

Returning to FIG. 1, when treatment vehicles 16 have resin requiringregeneration, they are transported to the resin transfer hub 22. Spentresin is transferred from the treatment vehicle 16 at the resin hub 22to a resin storage vessel 24 or directly into a resin transport vehicle28. Optionally, a resin transport vehicle 28 may be used as a resinstorage vessel 24 by leaving it at the resin forwarding hub 22.Regenerated resin from another resin storage vessel 24 or resintransport vehicle 28 is transferred through the resin hub 22 to re-fillthe treatment vehicle 16. The treatment vehicle 16 can be put back inservice at the same or another treatment site 18. If the spent resin wasfirst transferred to a resin storage vessel 24, it is re-transferredthrough the resin transfer hub 22 to a resin transport vehicle 28. Theresin transport vehicle 28 is then transported to the service centre 14.The resin is regenerated at the service centre 14, and the resintransport vehicle 28 is re-filled with regenerated resin to be returnedto the resin transfer hub 22.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

1. A system for providing temporary or mobile water treatment using ionexchange resins comprising, a) a service centre adapted to regenerateone or more types of ion exchange resins; b) a treatment vehiclecomprising a tank for holding resin and adapted to permit water beingtreated to flow through the resin; c) a resin transport vehicle; and d)a resin transfer hub for moving resin between the treatment vehicle andthe resin transport vehicle.
 2. The system of claim 1 wherein thetreatment vehicle comprises a trailer adapted for transport by road. 3.The system of claim 1 wherein the resin transport vehicle comprises atank mounted to a frame and the frame is adapted to be carried onanother vehicle.
 4. The system of claim 3 wherein the resin transportvehicle is sized, and comprises connectors, such that the resintransport vehicle may be transported through an inter-modaltransportation system.
 5. The system of claim 1 wherein the resintransfer hub is provided on or in a vehicle.
 6. The system of claim 5wherein the vehicle is a shipping container.
 7. The system of claim 1further comprising a resin storage vessel connected to the resintransfer hub.
 8. The system of claim 7 wherein the resin storage vesselcomprises a silo.
 9. The system of claim 1 wherein the resin transferhub comprises a water tank, a water recirculation pump and an aircompressor.
 10. The system of claim 3 wherein the resin transportvehicle further comprises an inlet near the top of the tank and anoutlet near the bottom of the tank.
 11. The system of claim 1 furthercomprising a tank containing polishing resin connected to an inlet tothe resin transfer hub.
 12. A process for providing regenerated resin toa mobile water treatment vehicle comprising the steps of, a) moving thewater treatment vehicle to a resin transfer hub; b) using the resintransfer hub to move spent resin from the mobile water treatment vehicleto a resin transport vehicle; and, c) using the resin transport hub tomove regenerated resin from another resin transport vehicle to the watertreatment vehicle.
 13. The process of claim 12 further comprising a stepof transferring the spent resin to a service centre where the spentresin is regenerated.
 14. The process of claim 13 further comprising astep of transporting the regenerated spent resin to the resin transferhub.
 15. The process of claim 13 wherein the step of transferring thespent resin to a service centre occurs at least in part by rail or boat.16. The process of claim 13 wherein the resin transfer hub is located inan area of water scarcity relative to the service centre.
 17. Theprocess of claim 12 wherein the water treatment vehicle is located in atrailer and step a) comprises towing the water treatment vehicle overroads.
 18. The process of claim 12 wherein step b) or step c) comprisesa step of storing resin temporarily in a vessel near the resin transferhub during the movement of the resin.